Method and apparatus for catalytically heating wellbores

ABSTRACT

A catalytic heater is used in supplying heat to wellbores and has a catalytic surface open to the wellbore for contacting and causing the reaction of a fuel mixture. The preferable catalytic material is platinum supported on a matrix of asbestos, asbestosburlap, ceramic, or other non-combustible material. Air and fuel gas is injected into the wellbore to contact the catalyst. Initiation of a catalytic reaction is brought about by use of a fuel gas containing hydrogen which will spontaneously react with air at standard conditions in the presence of the catalyst. Once the hydrogen-air reaction reaches the reaction temperature of a hydrocarbon fuel gas and air, hydrogen injection is terminated. A carrier fluid may be used to transport the heat of reaction to a formation or other appropriate location.

United States Patent [19] Berry et al.

[ METHOD AND APPARATUS FOR CATALYTICALLY HEATING WELLBORES [75] Inventors: Holland J. Berry; William C. Hardy;

Dale W. Zadow, all of Dallas, Tex.

[73] Assignee: Sun Oil Company, Dallas, Tex. [22] Filed: Sept. 1, 1972 [2]] Appl. No.: 285,781

Related U.S. Application Data [60] Division of Ser. No. 92,836, Nov. 25. 1970, Pat. No. 3,712,375, which is a continuation-in-part of Ser. No. 889,059, Dec. 30. 1969, abandoned.

Hunt 166/59 5] June 18, 1974 1/1969 Todd 166/59 X 2/1970 Hujsak et al 166/59 5 7] ABSTRACT A catalytic heater is used in supplying heat to wellbores and has a catalytic surface open to the wellbore for contacting and causing the reaction of a fuel mixture. The preferable catalytic material is platinum sup ported on a matrix of asbestos, asbestos-burlap, ceramic, or other non-combustible material. Air and fuel gas is injected into the wellbore to contact the catalyst. Initiation of a catalytic reaction is brought about by use of a fuel gas containing hydrogen which will spontaneously react with air at standard conditions in the presence of the catalyst. Once the hydrogen-air reaction reaches the reaction temperature of a hydrocarbon fuel gas and air, hydrogen injection is terminated. A carrier fluid may be used to transport the heat of reaction to a formation or other appropriate location.

27 Claims, 3 Drawing Figures PATENTEfiJlmmm 3317332 SHEET 2 OF 2 AIR COMPRESSOR 3 NATURAL GAS METHOD AND APPARATUS FOR CATALYTICALLY HEATING WELLBORES BACKGROUND OF THE INVENTION This application is a division of co-pending application, Ser. No. 92,836, filed Nov. 25, 1970 entitled Method and Apparatus for Catalytically Heating Wellbores, now U.S. Pat. No. 3,712,375, which is a continuation-in-part of Ser. No. 889,059, filed Dec. 30, 1969, now abandoned, entitled CATALYTIC IGNI- TION OF EARTH FORMATIONS.

This invention relates to a catalytic heater for use in supplying heat to a wellbore, and is related to two copending applications filed of even date with Ser. No. 889,059, entitled METHOD AND APPARATUS FOR IGNITION AND HEATING OF EARTH FOR- MATIONS, Ser. No. 889,061 issued as U.S. Pat. No. 3,680,636, and METHOD AND APPARATUS FOR IGNITING WELL HEATERS, Ser. No. 889,060 issued as U.S. Pat.'No. 3,680,635. In addition this invention relates to a divisional application of Ser. No. 889,060 entitled Method and Apparatus for Igniting Well Heaters bearing Ser. No. 255,882, filed on May 15, 1972. Several methods have been employed for heating'wells for wellbore clean-out, sand consolidation, in situ combustion, etc. These methods have included downhole electrical heaters, gas burners and catalyticreactors. Air is flowed down the annulus of the oil well and its temperature is raised by the heater which is supplied with a fuel gas in the case of the gas burner and catalytic reactor. Electrical energy in lieu of fuel gas is used in the electrical heater.

The use of electrical heaters has been limited to shallow wells due to the difficulty related to supplying adequate electrical power at depths in excess of 3,000 feet. High voltages are required for operation of the electrical heater and when the electrical cable exceeds about 3,000 feet, the resistance in the cable reduces the downhole voltage below that required for operation of the electrical heater. Also, the electrical heaters have a tendency to short out owing to hot spots developing through poor heat exchange resulting from coke formation on its surface. The temperature in this coke layer will build up until it exceeds the melting point of the heating elements, causing the electrical heater to fail. Additionally, a source of electrical energy is not always available in remote areas, which necessitates use of a large generator.

The drawbacks related to gas fuel burners relate to damage to well equipment because of the high combustion temperature of natural gas which can approximate 4,000 E. At this temperature, the heat shield, tubing,

and easing may be damaged, especially if the flame stands off from the nozzle where the fuel gas exits. When a stand-off flame extends below the heat shield for an appreciable period of time, the unprotected casing will be damaged and if the wellbore is uncased, formation permeability may be damaged in the vicinity of the wellbore.

In the case of both gas burners and catalytic reactors, there are problems realted to ignition of the burner or commencement of the catalytic reaction. Currently, gas burners are being ignited by pyrophoric chemicals with necessitates purging the tubing of air with nitrogen, since such chemicals ignite in the presence of air at standard conditions. The pyrophoric chemical is lowered to the burner where it contacts a mixture of fuel gas and air which will explode if the mixture is too rich, and will not ignite if too lean. lrreparable well damage can result from an explosion, and the tedious purging procedures must be repeated if the burner fails to ignite due to a lean mixture.

Catalytic heaters are known in the art; however, ignition temperatures of the fuel gases employed required an external source of heat. This heat has been provided by preheating the fuel gas or by heating the catalytic surface itself. A propane-air fuel mixture requires fuel preheating of at least 600 F. for its reaction at the catalytic surface; and a methanol-air fuel mixture requires preheating to at least 200 F. Additionally, present catalytic heaters are enclosed systems requiring expensive equipment and resulting in inefficient heat exchange to the formation. It is therefore an object of the present invention to provide an improved downhole catalytic heater and method of initiating the catalytic reaction.

SUMMARY OF THE INVENTION With these and other objects in view, the present invention contemplates use of a catalytic downhole heater completely open to the interior of the wellbore and/or arranged in a heat shield having air inlets with adjacent baffles for imparting turbulence to air enter ing the heat shield. This heater is initiated by injection of a fuel mixture comprising hydrogen and natural gas in a volumetric ratio of approximately 1 to 4, respectively. Also it can be initiated by using a wireline operated electrical system which provides heat to a heating element built into the catalytic heater.

Alternatively, catalytic material is placed in the wellbore adjacent a formation or area being heated, so that the fuel gas would flow through the catalytic material on its way to the formation or other area. Also, powderized catalytic material may be carried into a formation adjacent the wellbore by air injected into the forma tion. A complete understanding of this invention may be had by reference to the following detailed description, when read in conjunction with the accompanying drawings illustrating embodiments thereof.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of a catalytic heater located in a downhole position seated inside a heat shield;

FIG. 2 is a cross section along lines 2-2 of the catalytic heater of FIG. 1; and

FIG. 3 is a cross-section of catalytic material placed in the wellbore, opposite a formation being heated.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIG. 1 of the drawings, there is seen a retrievable catalytic heater located in a wellbore.

The heater 38 is located inside of an extending through the tubing 14 with the lower end having a catalytic surface 40 surrounded by an open bottomed heat shield 26. The heat shield is attached to the tubing 14 by attachment members 20. This heat shield 26 is optional as will be better understood hereinafter.

Baffles shown at 58 in FIG. 2 are adjacent to the attachment members 20. The heater 38 shown in FIG. 1 is rested on seating nipple 54 which contacts the nogo flange 28 of the heater 38. An O-ring seal assembly 52 is employed to seal the heaters catalytic exterior 40 from the tubing interior.

The upper portion of the heater 38 has a cable head and thermocouple hanger assembly 24 for connecting a double armored high temperature thermocouple cable 16. The hanger assembly 24 is positioned above the no go" flange 28 and is separated therefrom by upper stand-off member 32. The upper stand-off member 32 has gas inlet ports 22 which are channels extending through the side wall of the stand-off member 32. Gas flows to the interior of the heater 38 through upper stand-off member 32, seating nipple 54, lower stand-off 34 and gas distribution tube 44. Tube 44 extends through the catalytic portion of the heater 38. The catalytic portion of the heater 38 comprises catalytic material on a support having a surface 40 held by heater screen 36. A fiberized silica material 42 such as FIBER- GLASS or CERAFELT is located between the distributor tube 44 and the catalytic surface 40. The supported catalytic material is arranged so that spaces are present between the particles of the catalytic material and therefore the material defines fluid flow passageways. Located on the catalytic surface is a skin thermocouple 46 which is connected to the thermocouple cable 16.

Attached to the lower end of the catalytic portion of the heater is a sub 70, housing a temperature pill holder 50 and a hot air thermocouple 48. The hot air thermocouple 48, like the skin thermocouple 46 is connected to the thermocouple cable 16. These thermocouples transmit an electromotive force signal which is carried by the thermocouple cable 16 to an indicator located at the surface (not shown).

To ensure that the tubing 14, heat shield 26, and heater 38 are properly positioned in the casing 12, centralizers 68 are attached to the exterior of the tubing 14 just above the top of the heat shield 26.

M the operation of this heater one component of a fuel mixture (usually air) is passed down the annulus between tubing 14 and casing 12. The remaining portion of the fuel mixture (usually a hydrocarbon gas) is flowed down the tubing interior, passes through fuel passages 22 to enter gas distributing tube 44 located in the interior of the heater 38. This remaining portion of the fuel mixture then flows down distributing tube 44; enters the catalytic portion of the heater 38', passes through perforations in the wall of the distributing tube 44; enters the area occupied by the silica material 42; contacts the catalytic material; and exits the heater 38 by passing through the catalytic surface 40. Since the component of the fuel mixture descending the annulus enters the heat shield 26 by way of air inlets 18 it comes into contact with the catalytic surface 40 and the complete fuel mixture is available for reaction.

When the heater 38 is being used for heating a formation 56 adjacent the wellbore, a gas is initially pumped into the formation to force reservoir fluids away from the wellbore. After these reservoir fluids have been cleared from the wellbore and adjacent formation, fuel gas is injected into the tubing 14 and passes through fuel passages 22 to enter gas distributing tube 44 located in the interior of the heater 38. The gas flows down tube 44 and enters the catalytic portion of the heater 38. The fuel gas is diffused by the baffling action of the fiberized silica material 42, and contacts the catalytic material, whereupon it exits the heater 38 by passing through catalytic surface 40. The fiberized silica material CERAFELT has excellent heat resistant properties which are desirable in this use. Upon exiting the catalyst the fuel gas is in communication with the injected air which enters the heat shield 26.

To initiate the catalytic reaction, a fuel gas is used preferably comprised of natural gas and hydrogen in a 4:1 ratio. A hydrogen slug preceding the natural gas can also be employed as well as ratios of natural gas to hydrogen from 1:1 to In the presence of a catalytic material such as platinum, the hydrogen will react with air at temperatures in excess of approximately F. The hydrogen air reaction will raise the temperature in excess of the catalyzed reaction temperature of natural gas and air which approximates 250 F. Once the natural gas and air react, the hydrogen portion of the fuel gas is no longer needed. Indications of the natural gas-air reaction is derived from the information transmitted by the skin thermocouple 46 and hot air thermocouple 48.

Another method of initiation of a catalytic reaction of natural gas and air is by heating the catalytic heater with a battery powered ignitor supplying energy to a heating coil located adjacent the heater.

Utilization of the hydrogen-natural gas fuel mixture besides providing spontaneous ignition of the heater, also allows a high fuel injection rate and makes the possibility of an explosion less likely than if pure hydrogen is used. If hydrogen alone were used only about 6 cubic feet of hydrogen per hour per square foot of catalyst surface could be injected. With a natural gas-hydrogen mixture, injection rates can be increased to 20-25 standard cubic feet per hour per square foot of catalyst surface. After initiation of the natural gas-air reaction and cessation of the injection of the hydrogen portion of the fuel, the fuel injection rate should be supplied at the rate of 20-45 SCF/hr/ft of catalyst surface, depending on heat requirements and information received from the thermocouples 46 and 48.

In an in situ combustion operation, air flowing inside the heat shield entering through inlets 18 is divided between air entering into the reaction with the catalyzed fuel gas, and air which acts as a carrier of the heat generated by such reaction. This heat carrier air upon exiting the heat shield mixes with the air flowing down the annulus which does not enter the heat shield. This mixing raises significantly the temperature of the entire air stream entering the formation 56.

The hot air thermocouple 48 is located below the heat shield in order to be exposed to the air stream consisting of heat carrier air and air flowing through the annulus 13. The thermocouple 48 thus would be indicative of the temperature of the air entering the formation 56. The baffles 58 shown in FIG. 2 located adjacent the upper air inlets 18 ensure a turbulent air stream for contacting the natural gas-air reaction and for mixing with the air flowing down the annulus 13 which does not enter the heat shield.

The temperature pill holder 50 is located adjacent the hot air thermocouple 48 and contains pills which melt at different temperatures so that the highest temperature attained can be determined. Accurate temperature information is important in determining whether the thermocouple 48 is transmitting accurate information. Also, in case of damage to the well caused by excessive downhole heat, the pills could be used to determine the highest temperature attained for analysis of the causes of damage.

if the natural gas-air reaction should go to flame, temperatures approximating 4,000 F. could be reached, and if that temperature were reached for any appreciable time period, damage to downhole equipment would result. Accordingly, the reaction should not be allowed to go to flame, and preferably would be maintained at a level below l,000 F. This would be several hundred degrees below the temperature that the reaction would go to flame, thereby affording a sub stantial safety factor. Because the temperature is kept below that which wouldcause damage to well pipe, the heat shield 26 is not necessary.

To pre'ventan explosive mixture of air and fuel gas, the air to fuel ratio should be in the range of 30 to 60. An explosive mixture of methane is to methane by volume with the remainder air and the explosive range for hydrogen is 4 to 74% hydrogen by volume. Therefore, an explosive mixture will be avoided if the air to fuel ratio is at least 25 to 1.

If the thermocouples indicate that the reaction has gone to flame, it can be quickly snuffed out by cutting back on the fuel injection rate. It has been observed that the downhole temperature decreases rapidly in response to a cut back in fuel and increases at a much slower rate when the fuel injection rate is increased. It would therefore be expected that the operation could be at least partially automated with injection rate controls acting in response to thermocouple information. An alarm system would be necessary in a semiautomated system when excessive temperatures are reached.

FIG. 2 is a cross-section along lines 2-2 of the heater and heat shield shown in FIG. 1. The tubing 14 is located inside of the casing 12 with a heat shield 26 attached to the lower portion of the tubing by attachment members 20. Air inlets 18 are located in the wall of the heat shield 26. The baffles 58 are arranged so as to impart turbulence to the air entering upper air inlets 18. This turbulent air flow insures a complete reaction of the air and fuel gas on the catalytic surface of the heater 38 as well as diminishing the likelihood of hot spots developing inside the heat shield 26.

The catalytic material used may be selected from a wide list of materials and form no part of this invention. The preferable catalyst is platinum or a heat resistant support such as asbestos or ceramic material. Other catalysts suitable for oxidation of the fuel gas used herein include the platinum group metals and their oxides. Many other catalytic materials may be used in this reaction and are well known to those of average skill in the catalytic art.

The outside diameter of the catalytic heater 38 is smaller than the inside diameter of the tubing 14 allowing running and retrieval by wireline. The gas distributing tube 44 carries fuel gas to the catalytic area of the heater 38 where the fuel gas enters numerous small openings in the gas distributing tube 44 and contacts the fiberized silica material 42 such as CERAFELT which operates to disperse the fuel gases that it contacts a broader area of the catalytic surface 40. The fiberized silica 42 is arranged such that there is only a slight pressure drop as the fuel gas exits the heater 38. The heater screen 36 acts as a retainer for the supported catalytic material and provides a rigid shape to the catalytic area of the heater 38 so that it is not easily deformed.

Alternatively, a catalyst such as platinum oxide together with a support material such as aluminum silicate can be homogeneously formed in the shape of a hollow cylinder. The exterior of the cylinder may be sprayed with a cohesive agent such as sodium silicate to prevent fragmentation or crumbling. This heater construction affords a more effective fuel contact and elimination of the need for dispersing material 42 or heater screen 36, since the catalyst and support, together with a gas distributing tube 44, possesses sufficient rigidity to withstand wellbore running and retrieval.

FIG. 3 is illustrative of a system for heating a formation without need for special downhole equipment. Most wells have casing 12 and tubing 14 located in the wellbore although neither is essential to the operation described herein. The formation location should be fairly accurately determined as well as the area in the wellbore below the formation. lf liquids are present in the wellbore they should be bailed out. Coarse sand 60 of approximately l2 to 60 mesh is injected into the wellbore in avolume approximating the volume of the wellbore located below the formation to be ignited. Air is then pumped down the wellbore into the formation to be ignited at a rate sufficient to free the wellbore and formation 56 adjacent the wellbore, of fluids.

When the wellbore and adjacent formation 56 are freed of fluids, a catalytic material 62 supported on ceramic aggregate is injected into the wellbore in sufficient quantity to fill the wellbore adjacent the formation 56. A gas is continually pumped into the formation during the placement of the catalyst as the catalyst should be kept free from liquids to prevent contamination.

A fuel mixture containing hydrogen is then injected into the wellbore together with air. It is preferable to inject the fuel mixture into the tubing 14 and the air into the annulus 13 so that a combustible mixture is not present until the bottom of the wellbore is reached. Air injected at high pressure can become very hot at points of anomaly interposed in its path, thus causing ignition under certain circumstances.

Upon the fuel mixture reaching the catalytic material 62 on its path to the formation 56 the hydrogen spontaneously reacts with the air since the reaction temperature is around 20 F. When the reaction temperature of hydrogen and air reaches approximately 250 F., natural gas will react. Once the natural gas or other fuel has started to react, the hydrogen portion of the fuel is no longer needed. When heat is being supplied to the formation to initiate in situ combustion of formation fluids, production and pressure at adjacent producing wells can be monitored to determine when such combustion has commenced. Once commenced, the fuel gas is no longer needed.

The catalytic aggregate should be sized so that the passageway into the formation is not blocked or is not so blocked as to create a significant back pressure. Aggregate a quarter to a half inch in diameter should serve well in this regard. The points of contact between adjacent catalytic aggregate defmes air flow channels for the air entering the formation. Such a formation ignition procedure has the advantage of dispensing with downhole hardware and its related cost. The tubing need not be pulled to attach a seating nipple and heat shield. The catalytic material is readily available and inexpensive and therefore may be left in the wellbore or removed without regard to contamination.

In order to monitor the operation of this formation ignition procedure, a thermocouple is lowered on a high temperature thermocouple cable until it contacts the catalyst bed. Readings taken from the thermocouple would indicate whether a reaction was in process and if the injection rates should be modified to effect a temperature change.

Another method of catalytically igniting the formation is to operate in essentially the same manner described in the description of FIG. 3 up until injection of the catalytic aggregate. Those steps would be: the wellbore liquid removal, and gas injection to force the formation fluid away from the wellbore.

In lieu of injecting catalytic aggregate in the wellbore adjacent the formation, a powdered catalyst would be injected into the gas stream to be carried into the formation. A hydrogen containing fuel gas would then be injected to initiate a catalytic reaction. Once the temperature was raised to allow catalytic reaction of natural gas or other fuel, the hydrogen portion would be deleted. It should be noted that this process is essentially the same as that described in the description of FIG. 3, except that a powdered catalyst is carried into the formation by flow of the injected gas rather than remaining in the wellbore as would be the case for the catalytic aggregate.

While particular embodiments of the present invention have been shown and described, it is apparent that changes and modifications may be made without departing from this invention in its broader aspects, and therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of this invention.

What is claimed is:

1. Apparatus for providing heat in a wellbore comprising: a catalytic material having a flow channel therethrough located in the wellbore and openly communicating with the wellbore; means for passing one component of a fuel mixture through said flow channel; and means for passing the remaining portion of the fuel mixture into contact with the exterior surface of the catalytic material without passing through the flow channel.

2. The apparatus of claim 1 including at least one thermocouple located adjacent the catalytic material.

3. The apparatus of claim 2 wherein the catalytic material is run into the wellbore on a wireline which is constructed to act as a conductor cable for transmitting thermocouple information to the surface.

4. Apparatus for providing heat in a wellbore comprising: a catalytic material having a flow channel therethrough located in the wellbore and openly communicating with the wellbore; means for passing one component of a fuel mixture through said flow channel; and means for passing the remaining portion of the fuel mixture into contact with the exterior surface of the catalytic material, wherein the means for passing one component of a fuel mixture through the flow channel comprises well pipe and the means for passing the remaining portion of the fuel mixture into contact with the exterior surface of the catalyst comprises the annulus between the well pipe and the wellbore.

5. The apparatus of claim 4 wherein the catalytic material is in the form of a tubular member and wherein the interior of the catalytic tubular member communicates with the interior of the well pipe and the exterior of the catalytic tubular member communicates with the annulus.

6. The apparatus of claim 5 including a seating means attached to the lower end of the well pipe, sealing means between the catalytic tubular member and the seating means, and a flange member on the catalytic member for contacting the seating means and supporting the weight of the catalytic member, wherein the sealing means prevents direct communication between the well pipe interior and the catalytic member exterior surface.

7. Apparatus for supplying heat to a wellbore comprising: an uncontained supported oxidation catalyst located in a predetermined position in the wellbore, wherein said supported catalyst is formed to provide a fluids flow channel therethrough; and means for flowing a fuel mixture into the wellbore and into contact with said catalyst, said means for flowing a fuel mixture into the wellbore comprising first conduit means communicating with the fluids flow channel of the catalyst, and second conduit means communicating with the exterior surface of the catalyst and providing a fluids flow path to the exterior surface which does not bring fluids therein into contact with said fluids flow channel.

8. Apparatus for supplying heat to a wellbore comprising: a supported catalytic material located in the wellbore; means forming a first fluids flow channel through the catalytic material for passing first components of a fuel mixture to the catalytic material; and means forming a second separate fluids flow channel to the exterior surface of the catalytic material for passing second components of the fuel mixture to the catlaytic material wherein the first and second fuel components are not mixed until they are present on the exterior surface of the catalytic material.

9. Apparatus of claim 8 including means for supplying a fuel gas to said first fluid flow channel means and means for supplying air to the exterior of said catalytic material.

10. Apparatus for supplying heat to a wellbore comprising: a supported catalytic material located in the wellbore and completely open to the wellbore; and means forming a first fluids flow channel through the catalytic material said catalytic material being in tubular form and comprising a permeable inner wall, a permeable outer wall, and a baffling means therebetween.

with said catalyst through said fluids flow channel and second means for flowing the air into contact with the exterior surface of said oxidation catalyst, wherein fluids flowing through said first and second means are not mixed until they are contacted on the exterior surface of said oxidation catalyst.

13. Apparatus for supplying heat to a wellbore comprising: a supported oxidation catalyst suspended in the wellbore and completely open to the wellbore, saidcatalyst having a fluids flow channel therein; and means for flowing a fuel mixture to said catalyst, wherein the fuel mixture comprises a hydrocarbon gas and air and wherein the fuel mixture flow means comprises means for flowing the hydrocarbon gas into contact with said catalyst through said fluids flow channel and means for flowing the air into contact with the exterior surface of said oxidation catalyst, and wherein the hydrocarbon gas flow means comprises well pipe and the air flow means is the annulus between the well pipe and the wellbore.

14. The apparatus of claim 13 wherein the oxidation catalyst is shaped to provide an interior chamber which communicates with the well pipe interior and wherein the fluids flow channel comprises a multiplicity of passages through the wall of the chamber.

15. Apparatus for supplying heat to a wellbore comprising: an uncontained supported oxidation catalyst located in a predetermined position in the wellbore and having a plurality of passageways therethrough; means for passing one component of a fuel mixture into contact with the catalyst adjacent the passageways; means for passing the remainder of the fuel mixture into contact with the exterior surface of the catalyst; and means for monitoring the temperature adjacent the catalyst wherein the supported catalyst is formed to provide an interior surface and an exterior surface with a permeable thickness therebetween, and wherein the means for passing one component of a fuel mixture into contact with the catalyst adjacent the passageways comprises well pipe in communication with the interior surface of the supported catalyst, and further wherein the means for passing the remainder of the fuel mixture into contact with the exterior surface of the catalyst comprises the annulus between the well pipe and the wellbore.

16. Apparatus for supplying heat to a wellbore comprising: an uncontained supported oxidation catalyst located in a predetermined position in the wellbore and having a plurality of passageways therethrough; means for passing one component of a fuel mixture into contact with the catalyst adjacent the passageways; means for passing the remainder of the fuel mixture into contact with the exterior surface of the catalyst; and means of monitoring the temperature adjacent the catalyst, wherein the means for monitoring the temperature adjacent the catalyst comprises a thermocopple connected to the surface of the earth by electrical cable which also acts as means for lowering and retrieving the catalyst from the wellbore.

17. Apparatus for supplying heat to a wellbore comprising: an uncontained supported oxidation catalyst located in a predetermined position in the wellbore and having a plurality of passageways therethrough; means for passing one component of a fuel mixture into contact with the catalyst adjacent the passageways;

means for passing the remainder of the fuel mixture into contact with the exterior surface of the catalyst;

and means for monitoring the temperature adjacent the catalyst, wherein the supported catalyst is shaped in the form of a tubular member having perforated conduit means therein extending the length of said tubular member, and wherein the means for passing one component of a fuel mixture into contact with the catalyst adjacent the passageways comprises well pipe connected to said perforated conduit means.

18. Apparatus for supplying heat to a wellbore comprising: well pipe extending from the surface to a selected point in the wellbore and; a heater comprised of a supported oxidation catalyst having an interior surface in communication with the interior of said well pipe, an exterior surface completely open to the wellbores and a permeable wall between the interior and exterior surfaces.

19. The apparatus of claim 18 including means attached to the lower end of the well pipe for seating the heater, and means on the heater for engaging the seating means.

20. The apparatus of claim 19 including a perforated tubular member commencing from a point above the seatingmeans and extending through the heater adjacent the interior surface of the catalyst.

21. The apparatus of claim 19 including cable means attached to the heater for lowering the heater into the wellbore, at least one thermocouple positioned adjacent the heater, and means located in the cable means, for conveying thermocouple information to the earths surface.

22. The apparatus of claim 18 including means for monitoring the temperature adjacent the heater.

23. The process of providing heat in a wellbore having well pipe therein and an annular space between the well pipe and the wellbore, comprising the steps of: locating a catalytic material at the end of the well pipe, so that said material extends from the end of the well pipe; flowing one component of a fuel mixture through the well pipe and through the catalytic material; flowing the remaining portion of the fuel mixture down the annulus and into contact with the exterior surface of the catalytic material; and initiating a catalytic reaction of the fuel mixture.

24. The process of claim 23 wherein the component of the fuel mixture flowed through the well pipe and catalytic material comprises a hydrocarbon gas, and the remaining portion of the fuel mixture flowed through the annulus and into contact with the exterior surface of the catalyst comprises air.

25. The process of claim 24 including the step of flowing additional air down the annulus as an agent to transport heat.

26. The process of claim 23 wherein the catalytic reaction is initiated by flowing a hydrogen gas into contact with the catalyst whereupon a spontaneous hydrogen-air reaction occurs.

27. The process of claim 23 wherein the catalytic reaction is initiated by applying electrical current to a heating element located adjacent the catalytic material. 

2. The apparatus of claim 1 including at least one thermocouple located adjacent the catalytic material.
 3. The apparatus of claim 2 wherein the catalytic material is run into the wellbore on a wireline which is constructed to act as a conductor cable for transmitting thermocouple information to the surface.
 4. Apparatus for providing heat in a wellbore comprising: a catalytic material having a flow channel therethrough located in the wellbore and openly communicating with the wellbore; means for passing one component of a fuel mixture through said flow channel; and means for passing the remaining portion of the fuel mixture into contact with the exterior surface of the catalytic material, wherein the means for passing one component of a fuel mixture through the flow channel comprises well pipe and the means for passing the remaining portion of the fuel mixture into contact with the exterior surface of the catalyst comprises the annulus between the well pipe and the wellbore.
 5. The apparatus of claim 4 wherein the catalytic material is in the form of a tubular member and wherein the interior of the catalytic tubular member communicates with the interior of the well pipe and the exterior of the catalytic tubular member communicates with the annulus.
 6. The apparatus of claim 5 including a seating means attached to the lower end of the well pipe, sealing means between the catalytic tubular member and the seating means, and a flange member on the catalytic member for contacting the seating means and supporting the weight of the catalytic member, wherein the sealing means prevents direct communication between the well pipe interior and the catalytic member exterior surface.
 7. Apparatus for supplying heat to a wellbore comprising: an uncontained supported oxidation catalyst located in a predetermined position in the wellbore, wherein said supported catalyst is formed to provide a fluids flow channel therethrough; and means for flowing a fuel mixture into the wellbore and into contact with said catalyst, said means for flowing a fuel mixture into the wellbore comprising first conduit means communicating with the fluids flow channel of the catalyst, and second conduit means communicating with the exterior surface of the catalyst and providing a fluids flow path to the exterior surface which does not bring fluids therein into contact with said fluids flow channel.
 8. Apparatus for supplying heat to a wellbore comprising: a supported catalytic material located in the wellbore; means forming a first fluids flow channel through the catalytic material for passing first components of a fuel mixture to the catalytic material; and means forming a second separate fluids flow channel to the exterior surface of the catalytic material for passing second components of the fuel mixture to the catlaytic material wherein the first and second fuel components are not mixed until they are present on the exterior surface of the catalytic material.
 9. Apparatus of claim 8 including means for supplying a fuel gas to said first fluid flow channel means and means for supplying air to the exterior of said catalytic material.
 10. Apparatus for supplying heat to a wellbore comprising: a supported catalytic material located in the wellbore and completely open to the wellbore; and means forming a first fluids flow channel through the catalytiC material said catalytic material being in tubular form and comprising a permeable inner wall, a permeable outer wall, and a baffling means therebetween.
 11. The apparatus of claim 10 including a permeable retaining means encircling the permeable outer wall of the tubular catalytic material.
 12. Apparatus for supplying heat to a wellbore comprising: a supported oxidation catalyst suspended in the wellbore and completely open to the wellbore, said catalyst having a fluids flow channel therein; and means for flowing a fuel mixture to said catalyst, wherein the fuel mixture comprises a hydrocarbon gas and air and wherein the fuel mixture flow means comprises first means for flowing the hydrocarbon gas into contact with said catalyst through said fluids flow channel and second means for flowing the air into contact with the exterior surface of said oxidation catalyst, wherein fluids flowing through said first and second means are not mixed until they are contacted on the exterior surface of said oxidation catalyst.
 13. Apparatus for supplying heat to a wellbore comprising: a supported oxidation catalyst suspended in the wellbore and completely open to the wellbore, said catalyst having a fluids flow channel therein; and means for flowing a fuel mixture to said catalyst, wherein the fuel mixture comprises a hydrocarbon gas and air and wherein the fuel mixture flow means comprises means for flowing the hydrocarbon gas into contact with said catalyst through said fluids flow channel and means for flowing the air into contact with the exterior surface of said oxidation catalyst, and wherein the hydrocarbon gas flow means comprises well pipe and the air flow means is the annulus between the well pipe and the wellbore.
 14. The apparatus of claim 13 wherein the oxidation catalyst is shaped to provide an interior chamber which communicates with the well pipe interior and wherein the fluids flow channel comprises a multiplicity of passages through the wall of the chamber.
 15. Apparatus for supplying heat to a wellbore comprising: an uncontained supported oxidation catalyst located in a predetermined position in the wellbore and having a plurality of passageways therethrough; means for passing one component of a fuel mixture into contact with the catalyst adjacent the passageways; means for passing the remainder of the fuel mixture into contact with the exterior surface of the catalyst; and means for monitoring the temperature adjacent the catalyst wherein the supported catalyst is formed to provide an interior surface and an exterior surface with a permeable thickness therebetween, and wherein the means for passing one component of a fuel mixture into contact with the catalyst adjacent the passageways comprises well pipe in communication with the interior surface of the supported catalyst, and further wherein the means for passing the remainder of the fuel mixture into contact with the exterior surface of the catalyst comprises the annulus between the well pipe and the wellbore.
 16. Apparatus for supplying heat to a wellbore comprising: an uncontained supported oxidation catalyst located in a predetermined position in the wellbore and having a plurality of passageways therethrough; means for passing one component of a fuel mixture into contact with the catalyst adjacent the passageways; means for passing the remainder of the fuel mixture into contact with the exterior surface of the catalyst; and means of monitoring the temperature adjacent the catalyst, wherein the means for monitoring the temperature adjacent the catalyst comprises a thermocopple connected to the surface of the earth by electrical cable which also acts as means for lowering and retrieving the catalyst from the wellbore.
 17. Apparatus for supplying heat to a wellbore comprising: an uncontained supported oxidation catalyst located in a predetermined position in the wellbore and having a plurality of passageways therethrough; means for passing one component of a fuel mixture into contact with The catalyst adjacent the passageways; means for passing the remainder of the fuel mixture into contact with the exterior surface of the catalyst; and means for monitoring the temperature adjacent the catalyst, wherein the supported catalyst is shaped in the form of a tubular member having perforated conduit means therein extending the length of said tubular member, and wherein the means for passing one component of a fuel mixture into contact with the catalyst adjacent the passageways comprises well pipe connected to said perforated conduit means.
 18. Apparatus for supplying heat to a wellbore comprising: well pipe extending from the surface to a selected point in the wellbore and; a heater comprised of a supported oxidation catalyst having an interior surface in communication with the interior of said well pipe, an exterior surface completely open to the wellbores and a permeable wall between the interior and exterior surfaces.
 19. The apparatus of claim 18 including means attached to the lower end of the well pipe for seating the heater, and means on the heater for engaging the seating means.
 20. The apparatus of claim 19 including a perforated tubular member commencing from a point above the seating means and extending through the heater adjacent the interior surface of the catalyst.
 21. The apparatus of claim 19 including cable means attached to the heater for lowering the heater into the wellbore, at least one thermocouple positioned adjacent the heater, and means located in the cable means, for conveying thermocouple information to the earth''s surface.
 22. The apparatus of claim 18 including means for monitoring the temperature adjacent the heater.
 23. The process of providing heat in a wellbore having well pipe therein and an annular space between the well pipe and the wellbore, comprising the steps of: locating a catalytic material at the end of the well pipe, so that said material extends from the end of the well pipe; flowing one component of a fuel mixture through the well pipe and through the catalytic material; flowing the remaining portion of the fuel mixture down the annulus and into contact with the exterior surface of the catalytic material; and initiating a catalytic reaction of the fuel mixture.
 24. The process of claim 23 wherein the component of the fuel mixture flowed through the well pipe and catalytic material comprises a hydrocarbon gas, and the remaining portion of the fuel mixture flowed through the annulus and into contact with the exterior surface of the catalyst comprises air.
 25. The process of claim 24 including the step of flowing additional air down the annulus as an agent to transport heat.
 26. The process of claim 23 wherein the catalytic reaction is initiated by flowing a hydrogen gas into contact with the catalyst whereupon a spontaneous hydrogen-air reaction occurs.
 27. The process of claim 23 wherein the catalytic reaction is initiated by applying electrical current to a heating element located adjacent the catalytic material. 